This invention relates to heart retractors, and more particularly to heart retractors for expeditious coronary bypass operations.
In coronary bypass operations, grafts have to be anastomosed to the anterior descending artery, the circumflex artery, and the posterior descending artery. The anterior descending artery lies on the front surface of the heart, and is easily accessible to the surgeon without particular help from surgical assistants or using any devices. The circumflex and posterior descending arteries, however, lie on the back surface of the heart. Therefore, to expose the circumflex artery to a field of view of the surgeon it is mandatory to lift the heart and rotate the heart about the axis of the inferior vena cava and the superior pulmonary veins. Likewise, to expose the posterior descending artery it is mandatory to lift the heart and rotate the heart in the direction of its apex.
Ordinarily a surgical assistant is employed to lift the heart by the assistant's hand. However, it is very difficult to keep the heart in a steady position. Furthermore, the myocardium in contact with the assistant's fingers may be damaged by pressure, avulsion, and premature rewarming.
It has heretofore been proposed to use a heart support device in the form of a net for coronary artery surgery which is formed of a plurality of flat cloth tapes crossing each other at right angles and stitched to provide a mesh with square openings. A fixation tape having free ends extending laterally in opposite direction is stitched to the narrow portion of the net-like support to secure it to the heart of the patient. One of the extending portions of the fixation tape is placed under the aorta and pulmonary artery, and the other portion is placed under the inferior vena cava and by pulling up the net, the heart is lifted and kept in a steady position. But this heart support device is found to be unsatisfactory in coronary bypass operations. In the way of surgery, the tape in the mesh prevents an obstructed view of the back surface of the heart and the coronary arteries to be grafted are covered by the portions of the net.
Another proposed method to lift the heart is the use of slings placed underneath the heart. However, with this method certain experience has to be developed before they can be handled with ease, and still it is often difficult to expose the coronary artery to be grafted.